OCR computing exam questions
EXAM QUESTIONS AND
ANSWERS 100% CORRECT!!!
,(2013) Explain what is meant by an interrupt - ANSWER Interrupt sent to the processor
Request for processing time
Allows important tasks to be processed
(2013) State two types of interrupts - ANSWER Power failure
Software interrupt
Clock interrupt
(2013) Explain the need for interrupts to have priorities - ANSWER To decide between
interrupts and current task
To choose which interrupt if 2 occur
To ensure most urgent task is performed first.
To ensure most efficient use of processor
(2013) Describe segmentation - ANSWER A way of partitioning memory segments that
are not fixed size
Segments are logical divisions which complete sections the program.
(2013) State the purpose of virtual memory - ANSWER To allow programs to run when
there is insufficient memory available
(2013) Describe how virtual memory is used - ANSWER Use of backing store as if it
were main memory
Uses pages
Pages are moved from memory to backing store to make space for pages needed
(2013) Explain one problem that may occur while using virtual memory - ANSWER Disk
threshing
More time spent transferring pages than processing
(2013) Describe the code generation phase of translation. Your answer should include
reference to optimisation - ANSWER Code generation occurs after syntax analysis.
Produces a machine code program which is equivalent to the source program
Variables are given addresses
Relative addresses are calculated
Code optimisation makes code as efficient as possible
Increase processing speed
Number of instructions is reduced
Differences
, Parallel processors can use any processor for task
Co-processors performs specific types of task only
Parallel processors need a more complex operating system
Parallel processors are synchronised
(2013) Explain the term class - ANSWER A template for a set of objects that have state
and behaviour
They have methods and attributes represented by the rectangle on the diagram
(2013) Explain plain the term inheritance - ANSWER A derived class inherits all the
attributes and operations from its superclass shown by the arrow on the diagram
(2013) Explain the term capsulation - ANSWER Data hiding
Data can only be accessed using operations defined for the class
Maintains data integrity
(2013) Explain the need for registers - ANSWER Fast access to data for specific
purposes when frequent access is needed
Registers are used as a temporary storage
(2013) Explain the purpose of the accumulator when a program is being processed -
ANSWER Temporary storage in arithmetic logic unit
Holds data being processed during calculations
Deals with input and output in the processor
(2013) Explain why a composite key is used - ANSWER It creates one to many
relationships as a link table
It makes it 3NF
Reduces data inconsistencies
(2013) Describe features of a utility programs - ANSWER Used for the upkeep and
maintaining of the system eg virus checker
(2013) Describe the features of memory management - ANSWER Protect processes
from each other by partitioning
Forms of memory management include virtual memory, paging and segmentation
(2013) Tokens are used during compilation Describe tokens and state at what stage
they are created - ANSWER Created during lexical analysis
Used for reserved words
Each ticket is a string of binary digits of fixed length
EXAM QUESTIONS AND
ANSWERS 100% CORRECT!!!
,(2013) Explain what is meant by an interrupt - ANSWER Interrupt sent to the processor
Request for processing time
Allows important tasks to be processed
(2013) State two types of interrupts - ANSWER Power failure
Software interrupt
Clock interrupt
(2013) Explain the need for interrupts to have priorities - ANSWER To decide between
interrupts and current task
To choose which interrupt if 2 occur
To ensure most urgent task is performed first.
To ensure most efficient use of processor
(2013) Describe segmentation - ANSWER A way of partitioning memory segments that
are not fixed size
Segments are logical divisions which complete sections the program.
(2013) State the purpose of virtual memory - ANSWER To allow programs to run when
there is insufficient memory available
(2013) Describe how virtual memory is used - ANSWER Use of backing store as if it
were main memory
Uses pages
Pages are moved from memory to backing store to make space for pages needed
(2013) Explain one problem that may occur while using virtual memory - ANSWER Disk
threshing
More time spent transferring pages than processing
(2013) Describe the code generation phase of translation. Your answer should include
reference to optimisation - ANSWER Code generation occurs after syntax analysis.
Produces a machine code program which is equivalent to the source program
Variables are given addresses
Relative addresses are calculated
Code optimisation makes code as efficient as possible
Increase processing speed
Number of instructions is reduced
Differences
, Parallel processors can use any processor for task
Co-processors performs specific types of task only
Parallel processors need a more complex operating system
Parallel processors are synchronised
(2013) Explain the term class - ANSWER A template for a set of objects that have state
and behaviour
They have methods and attributes represented by the rectangle on the diagram
(2013) Explain plain the term inheritance - ANSWER A derived class inherits all the
attributes and operations from its superclass shown by the arrow on the diagram
(2013) Explain the term capsulation - ANSWER Data hiding
Data can only be accessed using operations defined for the class
Maintains data integrity
(2013) Explain the need for registers - ANSWER Fast access to data for specific
purposes when frequent access is needed
Registers are used as a temporary storage
(2013) Explain the purpose of the accumulator when a program is being processed -
ANSWER Temporary storage in arithmetic logic unit
Holds data being processed during calculations
Deals with input and output in the processor
(2013) Explain why a composite key is used - ANSWER It creates one to many
relationships as a link table
It makes it 3NF
Reduces data inconsistencies
(2013) Describe features of a utility programs - ANSWER Used for the upkeep and
maintaining of the system eg virus checker
(2013) Describe the features of memory management - ANSWER Protect processes
from each other by partitioning
Forms of memory management include virtual memory, paging and segmentation
(2013) Tokens are used during compilation Describe tokens and state at what stage
they are created - ANSWER Created during lexical analysis
Used for reserved words
Each ticket is a string of binary digits of fixed length
